Pouring table die block positioning device for an uphill vertical continuous casting machine

ABSTRACT

The invention relates to a device for positioning a die block ( 5 ) of a casting table ( 1 ) of a continuous vertical ascendant casting machine for pipes (T) with respect to a vertical axis of extraction (X—X), the die block ( 5 ) of the machine being fed by means of a device ( 3 ) for the supply of liquid iron, and bearing thereon. This positioning device comprises a retractable support ( 15 ) in which the die block ( 5 ) is fixed, a movable frame ( 6 ) on which the device ( 3 ) supplying liquid iron stands, means ( 18, 19 ) for relative positioning of support ( 15 ) with respect to frame ( 6 ), immobilising members ( 21, 25 ) designed to immobilise the relative position between support ( 15 ) and frame ( 6 ) in such a way that support ( 15 ), frame ( 6 ) and device ( 3 ) for the supply of liquid iron form an integral assembly, a base ( 40 ) arranged in a predetermined way with respect to the vertical extraction axis (X—X) which is designed to support the integral assembly, and means ( 47, 60, 64 ) for aligning the axis (Y—Y) of the die block ( 5 ) and the vertical extraction axis (X—X).

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the casting of molten metals, and moreparticularly to the continuous vertical ascendant casting of metalcomponents, such as cast iron pipes. Although the present inventionapplies to the casting of various types of metal components, it isparticularly advantageous for the casting of thin-walled, cast ironpipes. The expression “thin-walled pipes” refers to pipes having a smallthickness/diameter ratio, e.g., less than 10%, rather than the thicknessconsidered by itself in isolation.

2. Description of the Related Art

The invention relates more specifically to a device for positioning adie block in a machine for the continuous vertical ascendant casting ofcast iron pipes with respect to a vertical extraction axis. Such acasting machine incorporates a die block and a device for the supply ofliquid iron which feeds the die block through the lower end thereof.Such a supply device is, for example, described in document FR-A-2 705259 in the name of the Applicant. This device for the supply of liquidiron comprises a U-shaped siphon unit manufactured from cast refractoryconcrete, on which outlet the die block rests.

Given the high temperatures involved in the casting of molten metals,such a siphon unit becomes progressively worn and/or consumed by themolten iron which is in contact with it during the continuous castingprocess. In addition to this, when casting is stopped, solidification ofthe cast iron bursts the siphon unit.

As a consequence, this siphon unit must be replaced as a whole as soonas a particular number of pipes have been cast, i.e., is at everyshut-down.

Given that the siphon unit is a relatively massive component, and givenits location on the casting table of a casting machine in a pipeproduction system, in-situ replacement of the siphon unit is verydifficult, if not impossible. For this reason, the entire casting tablehas to be removed from the pipe production system in order that it canbe dismantled and the siphon easily replaced.

Furthermore, to shorten the length of the interruption in themanufacture of pipes several identical casting tables are usedalternately. When a siphon unit on one of the casting tables has to bereplaced, another is installed in the pipe manufacturing system.

However, when a casting table is replaced, alignment between the die andthe vertical axis along which the pipes are extracted gives rise to aproblem. In fact, the die block must be precisely aligned with thevertical extraction axis if the pipe manufacturing system to operatecorrectly. Now, given that the casting table has been completelydismantled, this alignment between the die block and the extraction axisis difficult and takes up a great deal of time, in particular on accountof the uncertain geometry of the refractory material parts used.

SUMMARY OF THE INVENTION

The purpose of this invention is to overcome this problem of positioningthe die block with respect to the vertical extraction axis by providinga die block positioning device through which rapid and precise alignmentbetween the die block and the vertical extraction axis can be achievedin order to reduce the length of interruptions in pipe manufacture.

With this object the invention relates to a device for positioning a dieblock of a casting table of a machine for the continuous verticalascendant casting of parts, in particular, pipes of cast iron, withrespect to a vertical extraction axis, in which machine the die block isfed via its lower end by a device for the supply of liquid iron andbears thereupon, a positioning device characterized in that it comprisesa retractable support in which the die block is fixed, a movable frameon which the device for supply of the liquid iron is placed, means forrelative positioning of the support with respect to the frame,immobilizing means intended to immobilize the relative position betweenthe support and the frame in such a way that the support and the frameform an integral assembly, a base arranged in a predetermined way withrespect to the vertical extraction axis, which is designed to supportthe integral assembly, and means for aligning the axis of the die blockand the vertical extraction axis.

The device according to the invention comprises one or more of thefollowing features:

the positioning means comprise at least two elongated members which areintegral with the support and corresponding guide members which areattached to the frame and which are each designed to receive anelongated member, or vice versa, the said members forming in particularshort column and ball-bearing socket assemblies,

at least one immobilizing member is a jack, in particular afluid-operated jack, connected to both the support and the frame,

at least one end of each jack is connected to the support and/or theframe by means of a mounting and a removable gudgeon to fix the end ofthe jack in the mounting,

the alignment means comprise means for relative positioning of the framewith respect to the base and means for adjusting the integral assemblyhorizontally,

the means for relative positioning of the frame with respect to the basecomprise at least a centering member, which is integral with the base,and projects therefrom in the direction of the frame, and acorresponding receiving member which is integral with the frame, or viceversa,

the member for centering or integral acceptance of the frame is alignedwith the axis of the die block and the member associated integrally withthe base is aligned with the vertical extraction axis,

the means for horizontal adjustment comprise several supporting jacksdistributed over the lower surface of the integral assembly,

at least one supporting jack is a screw jack.

The invention also relates to a casting table for a machine for thecontinuous vertical ascendant casting of parts, in particular, pipes ofcast iron, a casting table in which the die block is fed via its lowerend by a device for the supply of liquid iron and bears thereupon,characterized in that it comprises a positioning device as definedabove.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will be apparent from thefollowing description which is given by way of a non-restrictive examplewith reference to the appended drawings in which:

FIG. 1 is a side view of a casting table according to the invention,with a first cut-away at the inlet to the device for the supply ofliquid iron and a second cut-away at the outlet from this device;

FIG. 2 is a view of the casting table from above, in the direction ofarrow II in FIG. 1;

FIG. 3 is a view in transverse cross-section along the line III—III inFIG. 2;

FIG. 4 is a plan view of the top in the direction of arrow IV in FIG. 1;and

FIG. 5 is a view on an enlarged scale of detail V in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a casting table 1 of a machine for the continuous verticalascendant casting of parts, in particular pipes T, made of cast iron.This table comprises a device 3 for the supply of liquid iron and a dieblock 5 fed through its lower end by this supply device 3. The pipe T isextracted from the die block 5 by extraction means which are not shown,in an upward direction, along the vertical extraction axis X—X. Thedirection of the extraction force is represented by an arrow F.

The device 3 for the supply of liquid iron is placed on a frame 6 and isprevented from making lateral and vertical movements thereon by verticaltie bars 7 and horizontal cross-members 8. It incorporates a U-shapedsiphon 9 which is constructed in a single piece from cast refractoryconcrete.

This siphon 9 incorporates a molten iron feed conduit 10 comprising avertical descending part 10A for entry of the molten iron, a horizontalpart (which cannot be seen in the figures) and a vertical part 10Bthrough which the upwardly directed liquid iron exits.

With reference to FIG. 3, it will be seen that a heating base 11 isplaced between the die block 5 and the siphon outlet 9. A seal for themolten metal is provided by two annular sealing gaskets 12A and 12B, thefirst gasket 12A being located between the outlet of siphon 9 andheating base 11, and the second gasket 12B being located between theheating base 11 and the die block 5.

In addition to this, the siphon 9 and the heating base 11 are surroundedby a shell 13 in the thickness of which induction coils 14 are embedded.These induction coils 14 are provided with electrical current by anexternal generator, which is not shown, in order to keep the iron moltenas a result of induction heating.

The die block 5 is fixed in a retractable support 15 in the form of aplaten. This die block 5 comprises a cooling unit 17 linked to a coolingfluid circuit by inlet pipe 17A and outlet pipe 17B. On its uppersurface, cooling unit 17 has an extension of reduced diameter. Thisenters a matching receptacle 15A in the support 15 having vertical axisY—Y and is fixed by means of a crown of axial bolts 15B (FIG. 2).

The relative position of the support 15 with respect to the frame 6 isdetermined by two downwardly directed short columns 18, fixed to thesupport 15 in a diametrically opposite fashion with respect to the dieblock 5, as shown in FIG. 2. FIG. 3 shows that each short column 18 isguided in an associated socket 19, provided with ball-bearings, which isfixed to the frame 6.

Because the short columns 18 acting in conjunction with the ball-bearingsockets 19 are used, the relative position of the support 15 withrespect to the frame 6, and as a result the relative position of the dieblock 5 with respect to the frame 6, are precisely defined in a planeperpendicular to the vertical extraction axis X—X, while thesupport/frame distance can be adjusted parallel to the axis X—X.

In order to immobilize the position of the support 15 in relation to theaxis X—X with respect to the frame 6, two fluid-operated jacks 21, e.g.,hydraulic jacks or pneumatic jacks, are fixed in diametrically oppositepositions on the support 15 (FIG. 2). As illustrated in FIG. 3, eachjack 21 comprises a rod 22 whose free end 23 is fixed by a gudgeon 24 ina mounting 25 which is integral with the frame 6. Each gudgeon 24 issecured in the mounting 25 by pins (not shown) so that the support 15can be easily dismantled from the frame 6. The bodies 21A of the jacks21 are fixed to the upper surface of the support (platen) 15 by a collar21B.

As may be seen in FIG. 1, each fluid-operated jack 21 is connected by aconduit 26, 27 to a common conduit 29. This common conduit 29 isconnected to a hydraulic unit 31 which regulates the force with whicheach jack is tightened, and is shown diagrammatically. Advantageouslythis hydraulic unit is also mounted on the frame 6.

Once the position of the support 15 with respect to the frame 6 has beenimmobilized by the jacks 21, the support and the jacks, in addition tothe die block 5 and the supply device 3, form a rigid integral assembly.

The frame 6 rests on a fixed base 40 at four points of support. For thispurpose, the frame 6 has two horizontal supporting cross-members 42 ofsquare cross-section on its underside. As may be seen in FIG. 2, thesecross-members 42 are longer than the width of the frame 6 and extendbeyond the frame at the sides. As shown in FIG. 5, the cross-members 42each have a threaded hole 45 in each of their terminal zones, in a wall44 which is opposite base 40. A supporting bolt 46 is screwed into thehole 45 and forms therewith a jack 47 providing horizontal adjustmentfor the frame. The bolt 46 is prevented from rotating prematurely by alock nut 48. It will be understood therefore that the frame rests on thebase 40 through the lower ends of the four bolts 46.

In order that the Y—Y axis of die block 5 can be accurately positionedwith respect to axis X—X for the extraction of the pipe T, the frame 6also comprises a horizontal centering cross-member 56 of squarecross-section on its underside. With reference to FIG. 3, this centeringcross-member 56 has a wall 58 opposite the base 40 in which a centeringhole 60 is provided. This centering hole 60 is centered with respect tothe Y—Y axis of the die block 5. A protective cover 62 is located abovethe centering hole 60.

This centering hole 60 acts together without appreciable play with acentering pin 64 which is integral with the base 40. The base 40 isarranged in such a way that the vertical axis of the centering pin 64 isaligned with the extraction axis X—X of the extraction means.

Cooperation between this centering pin 64 and the centering hole 60makes it possible to bring a point on the axis of revolution Y—Y of thedie block 5 to coincide with the point on the vertical extraction axisX—X of the extraction means.

In order that the angular position of the frame 6 can also be fixed withrespect to the base 40, the frame 6 includes at its right hand extremityas seen in FIG. 1 an additional horizontal centering cross-member 70 ofsquare cross-section. This cross-member 70 includes in its wall 72opposite the base 40, in the center thereof, a centering groove 74 (seeFIG. 4) which acts with an additional centering pin 76 which is integralwith the base 40. This centering groove 74 is also protected againstunintended obstruction by a protective cover.

The frame 6 also includes horizontal cross-members 80, 82 and 84 ofsquare cross-section on its underside which are designed to render theframe 6 integral with the base 40. Cross-members 80, 82 and 70 includeholes in each of their lateral extremities designed to receive boltswhich are fixed in the base 40 in order to render the frame/baseassembly rigid after the frame 6 has been positioned with respect to thebase 40.

The space between the cross-members 56 and 82, and that between thecross-members 82 and 84, is provided for the forks of a pallet transferor so that the frame 6 can easily be removed together with the castingtable 1 so that the siphon 9 of the device 3 supplying molten iron canbe replaced.

As described earlier, the siphon 9 of the device 3 supplying liquidmetal must be regularly replaced. For this purpose the lateral fixingbolts in the cross-members 80, 82 and 70 are unscrewed and the frame 6is engaged by the forks of a pallet transfer or to move the assembly toanother place so that the casting table assembly 1 can be dismantled. Inorder to do this, the fixing gudgeons 24 in the mountings 25 arereleased, so that the assembly comprising the support 15 with the dieblock, short columns 18 and jacks 21 can be lifted off. Then it ismerely a matter of removing the tie bars 7 and the cross-members 8 inorder to proceed with the replacement of the worn siphon 9.

In order to position the die block 5 of a casting table 1 whose siphon 9has just been replaced, the short columns 18 are engaged in ball-bearingsockets 19. Then the free ends of the rods of the jacks 21 are securedin the mountings 25 using the gudgeons 24 and any movement in the latteris prevented by means of pins. Using a hydraulic unit 31, a certaintightening force is applied to the jacks 21 so that the die block 5bears against the supply means 3 crushing the gaskets 12A, 12B, with theheating base 11 being placed between the die block 5 and the supplydevice 3. As a result of this first relative positioning the axis ofrevolution Y—Y of the die block 5 housed in the cooling block 17 iscentered with respect to the centering hole 60 provided in the centeringcross-member 56.

Then the frame 6 which bears the flanged support 15 is placed on thebase 40 in such a way that the centering pin 64 engages the centeringhole 60, the angular position of the frame 6 with respect to the basebeing fixed by the additional centering pin 76 which engages thecentering groove 74. At this stage vertical extraction axis X—X and axisof revolution Y—Y of the die block 5 intersect in the vicinity of thecentering pin 60. In order to make the two axes coincide it is thensufficient to adjust the frame 6 horizontally on the base 40 using thebolts 46. The position of the bolts 46 is then immobilized using thelock nuts 48. Finally, to make the assembly rigid, bolts are screwedthrough the lateral holes provided in the cross-members 80, 82 and 70 inthe base 40.

The die can be aligned with respect to extraction axis X—X accuratelyand quickly by this means. As a result of this, downtime in the pipecasting system is greatly reduced.

What is claimed is:
 1. A device for positioning a die block (5) of acasting table (1) of a machine for the continuous vertical ascendantcasting of parts with respect to a vertical extraction axis (X—X), inwhich machine the die block (5) is fed through its lower end by means ofa device (3) for the supply of liquid iron, wherein said positioningdevice comprises: a retractable support (15) in which the die block (5)is fixed; a removable frame (6) on which the device (3) supplying theliquid iron is placed; means (18, 19) for relative positioning of thesupport (15) with respect to the frame (6); immobilizing means (21, 25)designed to immobilize the relative position between the support (15)and the frame (6) in such a way that the support (15) and the frame (6)form an integral assembly; a base (40) located in a predeterminedfashion with respect to the vertical extraction axis (X—X) and designedto support the integral assembly; and means (60, 64, 47) for aligningthe axis (Y—Y) of the die block (5) and the vertical extraction axis(X—X).
 2. A device according to claim 1, wherein the means for relativepositioning of the support (15) with respect to the frame (6) compriseat least two elongated members (18), which are integral with the support(15) and corresponding guide members (19) connected to the frame (6),each designed to receive an elongated member (18), or vice versa.
 3. Adevice according to claim 1 wherein at least one immobilising member isa fluid-filled jack (21) connected to both the support (15) and theframe (6).
 4. A device according to claim 3, wherein at least one end(23) of each jack (21) is connected to the support (15) and/or the frame(6) by means of a mounting (25) and a removable gudgeon (24) whichsecures the end of the jack (21) in the mounting (25).
 5. A deviceaccording to claim 1 wherein the means of alignment comprise means (60,64) for relative positioning of the frame with respect to the base andmeans (47) for horizontally adjusting the integral assembly.
 6. A deviceaccording to claim 5, wherein the means for relative positioning of theframe with respect to the base comprise at least one centering member(64) integral with the base (40) and projecting therefrom in thedirection of the frame (6) and a corresponding receiving member (60)integral with the frame (6), or vice versa.
 7. A device according toclaim 6, wherein the receiving member (60) which is integral with theframe (6) is aligned with the axis (Y—Y) of the die block (5), and thatthe at least one centering member (64) integral with the base (40) isaligned with the vertical extraction axis (X—X).
 8. A device accordingto claim 5 wherein the means for horizontal adjustment comprise aplurality of supporting jacks (47) distributed over the underside of theintegral assembly.
 9. A device according to claim 8, wherein at leastone supporting jack (47) is a screw jack.
 10. A casting table of amachine for the continuous vertical ascendant casting of parts, thecasting table (1) whose die block (5) is fed through its lower end bymeans of a device (3) for the supply of liquid iron, wherein saidcasting table comprises a positioning device in accordance with claim 1.